Such a particle spreader is provided with at least one particle supply for the particles to be strewed on the conveyor belt having at least one upper fill opening, an (overhead) chute being connected to the fill opening through which the particles enter the particle supply.
Wood material boards within the scope of the invention refers particularly to fiber boards, e.g. MDF (medium density fiber) boards. Particles refers particularly to fibers, e.g. MDF fibers. Such a particle supply is, for example, horizontally elongated and has a lower belt feeder, as well as a discharge device at the end of the belt feeder, e.g. a discharge roller front with several discharge rollers for discharging particles onto the particle conveyor belt. The conveyor belt is usually located below the particle supply. In the upper section, such a particle supply usually has an upper feeder, e.g. a drag bar feeder that feeds the particle entering the supply first upstream in the particle supply. This is to guarantee that the particle supply works according to the “first-in/first-out principle”. This is particularly significant when processing glued particles, for example, glued MDF fibers, so that the fibers entering the particle supply first are also the first to be removed from it and are strewed on the conveyor belt. The belt feeder on the bottom is also called the floor supply belt. By selecting the speed of the belt feeder, the stream of particles discharged from the particle supply can be set. Filling usually takes place by using a filler that can be provided with one or more cyclones and consequently can be provided with pneumatic feeders. These cyclones are usually provided with a cell wheel at the end or on the bottom. The particles are distributed by this cell wheel and then, by interconnection of various components, are fed into the chute, so that they enter the supply.
Particle spreaders of the type described above are known in practice in various embodiments. In principle, they have proven themselves. It is of particular significance that with the help of such a particle spreader, particle mats of flawless quality and a particularly even distribution of particle can be deposited on the conveyor belt. For this reason it is known to not strew the particles from the particle supply directly onto the particle feeder, but first to a scattering head that can, for example, be designed as a dispersion roller lane and which ensures an even dispersion of the particles. Moreover, it is known in this connection to provide a particle separator between the discharge roller arrangement of the particle supply and the scattering head or the dispersion roller lane, which has two particle-separating rollers for this purpose (compare DE 43 02 850 [U.S. Pat. No. 5,496,570]).
Furthermore, an apparatus for the creation of particle mats is known in which the particles are strewed on the conveyor belt by one or more belts via a fiber distribution or particle separator device. This device for loosening or distributing fibers is located directly above the conveyor belt and has two pairs of rollers that are located above each another and that rotate in the opposite direction of interlocking elements mounted on their outer surfaces (see U.S. Pat. No. 3,252,186).